df_DataBlock Class Reference
[IVD Data format.]

#include <df.h>

List of all members.

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Detailed Description

Class to handle one data block of specified size.

df_Datablock class is a wrapper class around raw memory buffer. It synchronises access to the memory block among a writer and reader(s).

It is used by df_BlockManager.

Author:

Matej Kenda, HERMES SoftLab

Definition at line 54 of file df.h.

Public Member Functions
	df_DataBlock (UInt8_t *a_block, const UInt32_t a_size)
bool	IsEmpty () const
bool	IsClosed () const
void	SetBlockID (UInt32_t a_blkID)
UInt32_t	GetBlockID () const
UInt8_t *	GetData () const
UInt32_t	GetBlockSize () const
UInt32_t	GetUsedSize () const
UInt32_t	GetFreeSize () const
	How much space is there to be processed? Used by the writer.
UInt8_t *	GetPosition () const
	Returns a pointer to the beginning of the free space.
void	Move (UInt32_t a_amount)
	Writing or reading data of a block is just increasing the amount of used space (a "virtual" pointer to the beginning of free space in a block).
void	Close (UInt32_t a_numReaders)
	Marks the block closed.
void	Release ()
	Each reader must release the block after it is finished with it.
void	Delete ()
	Deleting is resetting the amount of used space.
void	Wipe ()
	Currently not used.
Public Attributes
	log_CLASSID_m
Private Member Functions
virtual	~df_DataBlock ()
Private Attributes
UInt8_t *	m_block
const UInt32_t	m_size
	Size of the data block df_DataBlock::m_block.
UInt32_t	m_used
	How much of the block space is already used (written or read by front end).
bool	m_closed
	Writing to closed block is prevented.
UInt32_t	m_numReaders
	How many back-ends are left to finish processing this block.
UInt32_t	m_blockID
	Arbitrary block identification (e.g.
Friends
class	df_BlockManager
class	fsc_nsFSrecovery

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Constructor & Destructor Documentation

df_DataBlock::df_DataBlock	(	UInt8_t *	a_block,
		const UInt32_t	a_size
	)

Parameters:

	a_block	Pointer to the beginning of pre-allocated memory buffer.
	a_size	Size of memory buffer.

Definition at line 52 of file df_datablock.cpp.

    : m_block(a_block),
      m_size(a_size),
      m_used(0),
      m_closed(false),
      m_blockID(0) {

    // Empty
}

df_DataBlock::~df_DataBlock

(

)

[private, virtual]

Definition at line 62 of file df_datablock.cpp.

                            {
    // Empty
}

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Member Function Documentation

bool df_DataBlock::IsEmpty

(

)

const [inline]

Definition at line 85 of file df.h.

Referenced by Close(), df_Unpacker::GetNextBlock(), bea_MigrationThread::Migrate(), df_BlockReader::ReleaseAndGetNextBlock(), and df_MgrWriter::~df_MgrWriter().

{ return (m_used == 0); };

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bool df_DataBlock::IsClosed

(

)

const [inline]

Definition at line 86 of file df.h.

Referenced by df_Writer::GetNewBlock(), df_BlockManager::Release(), and df_MgrWriter::~df_MgrWriter().

{ return m_closed; };

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void df_DataBlock::SetBlockID

(

UInt32_t

a_blkID

)

[inline]

Definition at line 88 of file df.h.

Referenced by bea_VolumeReader::Run().

{ m_blockID = a_blkID; };

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UInt32_t df_DataBlock::GetBlockID

(

)

const [inline]

Definition at line 89 of file df.h.

Referenced by df_BlockReader::GetNextBlock(), and df_BlockReader::GetRawNextBlock().

{ return m_blockID; };

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UInt8_t* df_DataBlock::GetData

(

)

const [inline]

Definition at line 90 of file df.h.

Referenced by df_Unpacker::GetBSData(), df_Unpacker::GetNextBlock(), df_BlockReader::GetNextBlock(), df_BlockReader::GetRawNextBlock(), and bea_MigrationThread::Migrate().

{ return m_block; };

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UInt32_t df_DataBlock::GetBlockSize

(

)

const [inline]

Definition at line 91 of file df.h.

Referenced by df_Unpacker::GetBSData(), and bea_FRI::ReadFRI().

{ return m_size; };

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UInt32_t df_DataBlock::GetUsedSize

(

)

const [inline]

Definition at line 92 of file df.h.

Referenced by fsc_nsFSrecovery::FlushBlock(), df_Writer::FlushBlock(), and fsc_nsFSrecovery::~fsc_nsFSrecovery().

{ return m_used; };

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UInt32_t df_DataBlock::GetFreeSize

(

)

const

How much space is there to be processed? Used by the writer.

See also:

IsEmpty()

Definition at line 101 of file df_datablock.cpp.

References m_closed, m_size, and m_used.

Referenced by df_BlockProxyWriter::Allocate(), df_BlockProxyWriter::AllocateRawBlock(), Close(), df_BlockProxyWriter::GetFreeSize(), Move(), blk_NetReader::Run(), blk_BufferReader::Run(), and bea_VolumeReader::Run().

                                         {
    if (m_closed) {
        return 0;
    }
    else{
        return (m_size - m_used);
    }
}

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UInt8_t * df_DataBlock::GetPosition

(

)

const

Returns a pointer to the beginning of the free space.

Used by the writer.

Exceptions:

ivd_InternalError(ie_DF_BLOCKFULL)

Definition at line 115 of file df_datablock.cpp.

References ie_DF_BLOCKFULL, log_FUNC_m, m_block, m_closed, and m_used.

Referenced by df_BlockProxyWriter::Allocate(), df_BlockProxyWriter::AllocateRawBlock(), Close(), df_BlockProxyWriter::Go(), df_BlockProxyWriter::Move(), bea_FRI::ReadFRI(), blk_NetReader::Run(), blk_BufferReader::Run(), and bea_VolumeReader::Run().

                                         {
    if (m_closed) {
        log_FUNC_m(GetPosition);
        throw ivd_InternalError(ie_DF_BLOCKFULL, "Block is already closed.");
    }
    return (UInt8_t*)(m_block + m_used);
}

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void df_DataBlock::Move

(

UInt32_t

a_amount

)

Writing or reading data of a block is just increasing the amount of used space (a "virtual" pointer to the beginning of free space in a block).

Parameters:

a_amount

The amount of data that has been written to the block.

Exceptions:

ivd_InternalError(ie_DF_BLOCKFULL)

Warning:

Throws an exception if the data can't fit in the block. In fact, something has really gone wrong. Most probably the writing front end had already corrupted the memory buffer or reading front end had written over the block.

Definition at line 81 of file df_datablock.cpp.

References cmn_Num2Str(), GetFreeSize(), ie_DF_BLOCKFULL, log_FUNC_m, m_closed, and m_used.

Referenced by df_BlockProxyWriter::Allocate(), df_BlockProxyWriter::Go(), df_BlockProxyWriter::Move(), bea_FRI::ReadFRI(), blk_NetReader::Run(), blk_BufferReader::Run(), and bea_VolumeReader::Run().

                                         {
    if (m_closed) {
        log_FUNC_m(Move);
        throw ivd_InternalError(ie_DF_BLOCKFULL);
    }

    if (GetFreeSize() < a_amount) {
        log_FUNC_m(Move);
        throw ivd_InternalError(ie_DF_BLOCKFULL,
            "Free: " + cmn_Num2Str(GetFreeSize()) +
            " req: " + cmn_Num2Str(a_amount));
    }
    m_used += a_amount;
}

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void df_DataBlock::Close

(

UInt32_t

a_numReaders

)

Marks the block closed.

Nothing can be written to/read from the block until it is released. Used by writer.

Data block after useful data is filled with zeroes. That allows better compression on tape. However, if the block is logically completelly empty it is not wiped for performance optimization reasons.

Parameters:

a_numReaders

The number of readers that will process this block, before it is released.

See also:

Release()

Definition at line 136 of file df_datablock.cpp.

References GetFreeSize(), GetPosition(), IsEmpty(), log_FUNC_INT_m, m_closed, and m_numReaders.

Referenced by df_BlockManager::Flush().

                                              {
    log_FUNC_INT_m(Close);

    // Do not wipe out the block if it is completely empty.
    // The user of the class must detect that the block is logically empty.
    if ( !IsEmpty()) {
        UInt32_t wipeSize = GetFreeSize();
        memset(GetPosition(), 0, wipeSize);
    };

    m_closed = true;
    m_numReaders = a_numReaders;
}

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void df_DataBlock::Release

(

)

Each reader must release the block after it is finished with it.

df_DataBlock::m_readers gets decreased at each call.

Last reader also re-opens data block (sets df_DataBlock::m_closed to false) and deletes it (with Delete()).

Warning:

Each reader may call release only once for each data block.

See also:

df_BlockManager::Release()

Definition at line 160 of file df_datablock.cpp.

References Delete(), log_FUNC_INT_m, m_blockID, m_closed, and m_numReaders.

Referenced by df_BlockManager::Release().

                           {
    log_FUNC_INT_m(Release);

    m_numReaders--;
    if (m_numReaders == 0) {
        m_closed = false;
        m_blockID = 0;
        Delete();
    }
}

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void df_DataBlock::Delete

(

)

Deleting is resetting the amount of used space.

Called by Release().

Definition at line 172 of file df_datablock.cpp.

References m_used.

Referenced by fsc_nsFSrecovery::FlushBlock(), Release(), and Wipe().

                          {
    m_used = 0;
}

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void df_DataBlock::Wipe

(

)

Currently not used.

Wipe the whole contents of a block with zeroes?

Definition at line 179 of file df_datablock.cpp.

References Delete(), and log_FUNC_m.

                        {
    log_FUNC_m(Wipe);

    // Zero memory?
    Delete();
}

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Friends And Related Function Documentation

friend class df_BlockManager [friend]

Definition at line 104 of file df.h.

friend class fsc_nsFSrecovery [friend]

Definition at line 105 of file df.h.

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Member Data Documentation

df_DataBlock::log_CLASSID_m

Definition at line 61 of file df.h.

UInt8_t* df_DataBlock::m_block [private]

Definition at line 65 of file df.h.

Referenced by GetPosition().

const UInt32_t df_DataBlock::m_size [private]

Size of the data block df_DataBlock::m_block.

Definition at line 68 of file df.h.

Referenced by GetFreeSize().

UInt32_t df_DataBlock::m_used [private]

How much of the block space is already used (written or read by front end).

Definition at line 71 of file df.h.

Referenced by Delete(), GetFreeSize(), GetPosition(), and Move().

bool df_DataBlock::m_closed [private]

Writing to closed block is prevented.

Reopen at Delete(), which is called by Release() of the last back end.

Definition at line 75 of file df.h.

Referenced by Close(), GetFreeSize(), GetPosition(), Move(), and Release().

UInt32_t df_DataBlock::m_numReaders [private]

How many back-ends are left to finish processing this block.

Definition at line 78 of file df.h.

Referenced by Close(), and Release().

UInt32_t df_DataBlock::m_blockID [private]

Arbitrary block identification (e.g.

media position).

Definition at line 81 of file df.h.

Referenced by Release().

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The documentation for this class was generated from the following files:

• df.h
• df_datablock.cpp